EP 0 979 750 A2 describes a vehicle seat comprising an adjusting device with a spindle and an associated spindle nut. The spindle is fixed to a first adjustment element of the adjusting device. The spindle nut can turn in a second adjusting element, wherein the second adjusting element together with the first adjusting element is mounted in sort of a rail guide. With its outer casing, the spindle nut forms a worm wheel, which is engaged with a worm of a drive unit. The arrangement serves the displacement of a vehicle seat attached to the second adjusting element in relation to the first adjusting element, which is fixed to the vehicle bottom. The disadvantage associated with this arrangement is that it comprises a plurality of individual components, which must be disposed and attached directly in the rail arrangement formed by the two adjusting elements. Any potentially necessary repairs are therefore associated with great expenses.
U.S. Pat. No. 4,802,374 describes a control drive for a vehicle seat, wherein such a spindle is non-rotatably connected to a vehicle seat rail forming an adjusting element. The spindle, however, is fastened outside the rail guide, which is considered undesirable by vehicle manufacturers. A further seat adjustment device with a self-locking adjusting drive for vehicle seats is known from DE 1 755 740. Also in this arrangement, a plurality of components is disposed adjacent to a rail guide.
A gear arrangement with complex design for adjusting a vehicle seat is known from WO 02/070299 A1. This arrangement has a gear with complex design, which gear is intended to accommodate forces occurring in the event of an accident.
EP 1 068 093 B1 discloses a gear, as that illustrated according to FIG. 3, which is used to adjust two elements 60, 61 in relation to each other, particularly vehicle elements of a seat adjustment device, a window lifter or a sliding roof, wherein the first of the parts 60 forms a lower rail firmly connected to the vehicle bottom, which rail receives a locked spindle 62 or a fixed toothed rack. The gear 6 is located on the spindle 62 and displaced back and forth along the spindle 62 upon actuation. The gear 6 is received in a mount 63, which is displaced back and forth together with the second of the adjustable elements 61. The mount 63 is fixed to the second of the elements 61 adjustable in relation to each other, which second element forms a top rail that is adjustably connected to the bottom rail. The upper rail is connected to further components of the vehicle seat via a retaining plate 64. Furthermore, a drive mechanism 66 is attached to the retaining plate 64 using fastening elements 65, the drive shaft 67 of which mechanism is connected to a drivable worm of the gear 6.
The gear 6 comprises a worm wheel, with a spindle nut locked thereto for driving the spindle or a worm locked thereto for driving the toothed rack, a drivable worm for transmitting a driving force from the drive mechanism to the worm wheel and a gear housing, which receives and supports the worm and the worm wheel and is connected non-displaceably to the second of the adjustable elements 61 in the displacement direction. The gear housing comprises a plurality of, but at least two, housing plates that are fixed against each other with plug-type connectors. The plug-type connectors fix the positions of the housing plates in relation to each other in all three-dimensional directions, wherein the plug-type connectors are configured at the same time as supporting connecting joints, which absorb the gear forces. If only two housing plates are provided, the gear housing comprises two L-shaped housing plates. If at least four elements are provided, the gear housing comprises at least two pairs of mutually opposed disk-shaped housing plates, wherein in any case a complex gear arrangement is provided, which in addition to the housing elements necessitates a plurality of further bearing elements or bearing support elements, such as washers. Apart from the complex assembly of a plurality of individual components, it is also disadvantageous that the tolerances of the individual components must be adapted to each other. The individual housing elements of such a gear housing are connected by welding.
Furthermore it has been known to provide two individual pressure housing elements, which are equipped with a spindle nut, driver plates and bearing bushings as well as a worm and associated bearing bushings and are then closed through plastic deformation of plug-type connectors of the housing halves.
DE 36 40 197 A1 describes a drive apparatus for an adjustable power seat with a two-piece housing. In two opposed walls of the housing, respectively, a bore is formed for accommodating the shaft of a worm or of a worm wheel. So as to be able to support the shaft projecting from one end of the worm, a cover is inserted in front of the bore, which cover on the inside comprises a plug for supporting the shaft. In terms of the support of the worm wheel and the wheel, this concept has a two-piece housing, which is formed by a main housing and the absolutely required cover in terms of its function.
EP 0 992 711 A2 describes a gearbox for receiving a worm and a worm wheel, through each of which a shaft extends. The two shafts are mounted in two opposing recesses, wherein the recesses are formed by corresponding through-bores through the opposite side walls. So as to insert the worm wheel and worm in the housing, the housing comprises two members, wherein the respective parting line through the side walls extends at the center through the through-bores. After inserting the shafts of the worm and worm wheel in the recesses of the lower housing member, the upper housing member is placed on top and they are screwed together.
DE 41 04 470 C1 describes a car seat adjuster with a housing, in which a spindle nut and a threaded spindle are accommodated. The housing is a two-piece housing comprising a main housing element and a cover for closing the main housing element. A borehole is formed in a housing wall for receiving a drive shaft. The borehole extends laterally in a slot shape to an outside wall, which can be closed with the cover. The width of the slot corresponds to more than the width of the drive shaft and the width of the receiving section for the drive shaft in its respective functional position. Furthermore, the housing is very complex and comprises a plurality of individual wall and support elements.
DE 37 25 158 C2 relates to a power seat apparatus for an automotive vehicle, wherein a multi-piece housing with a worm and a worm wheel is shown. A plurality of different components are used for supporting the worm and worm wheel. DE 37 26 801 C2 relates to a worm gear with a housing, wherein the housing is divided by a partitioning plane that includes the driving axle and is disposed perpendicular to the driving axle, so that upon separation of the two housing members an opening is formed for inserting the worm wheel and worm. DE 35 19 058 C2 describes a seat adjustment for a motor vehicle seat with a complex housing for accommodating a worm and a worm wheel. A shaft is mounted in a U-shaped support, which is closed by a flat cover-shaped element in order to prevent the shaft from sliding out of the support. DE 29 25 032 C2 describes a drive unit for a seat adjustment with a multi-piece housing for accommodating a worm and a worm wheel. Particularly support elements, which are included in the housing parts as separate components, serve the support of shafts. DE 29 03 782 A1 relates to an adjustment mechanism with a complex design for receiving a worm and a worm wheel, wherein they are accommodated in special bearing elements.